The unconscious was central to the surrealists. Along the lines of Sigmund Freud's psychoanalytical theories, they wanted to go beyond the limits of the conscious mind, unleash the uninhibited and the irrational. In pursuit of this ambition, Ernst "invented" the frottage in 1925: by rubbing a pencil on paper he could transfer different patterns from the rough surface under the paper. Chance was the artistic motor; the conscious was merely one factor among others in the creative process. Out of the rough, moss-like surface of Human Figure a hybrid of bird, insect and plant emerges, with an unmistakable sexual undertone.